While the invention will be described in connection with a fuel cell and hydrogen/oxygen chemical reactions, the invention is by no means limited thereto. The liquid gas stripper may just as readily be used with any liquid stream containing a dissolved oxidant gas or gas mixture.
The production of electric power utilizing hydrogen/oxygen fuel cells is well known to the art, especially for use on spacecraft. In such cells, a reactant gas such as hydrogen is oxidized at the anode electrode associated with one side of an ion exchange membrane with the release of electrons. The electrons flow through the external load while the oxidized hydrogen ion is transported through the ion exchange membrane to a cathode electrode associated with the other side of the membrane. An oxidant such as oxygen, fluorine, chlorine, or bromine, is supplied to the cathode. The oxygen is reduced by addition of electrons and combines with hydrogen ions transported across the membrane to form a product liquid such as water. The product liquid formed at the cathode must be removed because it tends to form a film which blocks more oxidant from reaching the electrode. A wetproofing or hydrophobic film may be applied to the cathode to cause the water to bead; thereby preventing the formation of the water film. The beads of water are then removed using a wicking system or an internal hydrophilic porous media.
The by-product water, once removed, can be utilized in various fashions. However, problems arise due to oxygen saturation. If the water is stored, the liberation of oxygen can occur; consuming a volume of the storage facility. In space applications, for example, water can be stored in flexible bladders. When the water is removed for use, some oxygen remains within the bladder, accumulating, and eventually filling the bladder. With the limited storage space, this can cause serious problems. Furthermore, the water which is removed still contains a significant amount of dissolved oxygen. When it is used for ingestion by astronauts, the dissolved oxygen causes discomfort.
It is an objective of this invention to provide an improved technique for the removal of an oxidant from a water stream.